University of Arkansas, Fayetteville Division of Agriculture


Rice moisture content (MC) must be reduced to approximately 12.5% MC to prevent spoilage during storage. Desiccants may provide an improved method for drying research-scale rice samples. This study investigated the effects of 1) rice mass to be dried, 2) placement method of silica gel packets in rice samples, 3) regeneration and re-use of the packets, 4) drying temperature, and 5) initial MC on the effectiveness of silica gel packets to dry rough rice samples to the desired 12.5% MC. Multiple masses (200, 500, and 1000 g) of long-grain rice samples were dried using three desiccant placement treatments: 1) intimate mixing (IM) of silica gel packets without agitation, 2) intimate mixing and agitation (IMA), and 3) surface placement (SP) of silica gel packets on top of the rice samples. The IMA treatments produced little variability in final MCs across the three masses used. The adsorptive capacity of silica gel packets in 200-g samples of two rice cultivars was measured. The adsorptive capacity varied from 26 to 35%. Effects of rice initial MC and drying temperature were measured by drying samples at initial MCs from 13 to 18% at 10°C, 20°C, and 30°C for eight days. Increased drying temperatures produced decreased final MCs for both cultivars, which became more pronounced as the initial MCs increased.